Toogood joins from Rolls Royce where she was a business development director.
L&G is making a major push into the housing market using modern methods of construction.
It is producing precision-engineered manufactured units at the new 550,000 sq ft factory in Leeds which can produce up to 3,500 homes per year.
Toogood takes up her new role later this month.
Prior to joining Rolls-Royce she trained with Ernst & Young as a chartered accountant and holds an MBA in Strategy & Procurement.
She also served for eight years as a non-executive board member of Derwent Housing Association.
Nigel Wilson, CEO of Legal & General, said: “Rosie is joining the business at an exceptionally exciting time.
“Almost every other industry has seen radical innovation brought about by digital technology advancements. And yet we continue to build houses the same way that the Victorians did.
“We need more entrants to the sector, new technologies and business models to deliver the 100,000 shortfall of new homes.
“Just as the car industry was automated, so the UK’s traditional house building sector now needs to step up.
“We need to build houses faster and more efficiently than ever before. Rosie has a mandate to deliver this.”
Paul Stanworth, CEO of Legal & General Capital, said: “Rosie joins from a world leading, quality engineering organisation, where she managed complex commercial relationships and delivered large scale, customer-focused product.
“She is a strong hire and will provide important leadership for our modular housing business as it reaches the crucial delivery stage.
“Modular building is quicker and more efficient, and delivers at least the same or higher standards of building as traditional methods but with greater certainty.
“Crucially it is also far less labour intensive, providing additional capacity to the established UK housing sector at a critical time.
“It offers an economically viable solution and will deliver much needed scale.”